How to update Lollipop (Android 5.0) on a rooted nexus device

On a rooted nexus device with Lollipop (Android 5.0) the common OTA-updates fails. The reason is: there are some additional security checks while the OTA-update, which fails on rooted devices.

But if you know how to handle the adb-tools, it’s easy to make a manually update. Just download the matching factory image for your android device and extract the following files: boot.img, recovery.img and system.img.